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CatsJam's avatar
CatsJam
New Contributor
6 years ago

Daily SYNC Timing Synchronization failures and dropped internet connection

Since moving into our new house in June 2018, we continue to lose internet connection regularly.  It happens usually once a day, but sometimes multiple times a day.  Each time it is accompanied by the dreaded "SYNC Timing Synchronization failure" error (current modem event log copied below, along with current connection details).  Our first modem was the Netgear CM1000.  After troubleshooting online and over the phone with Cox and being told everything looked fine on their end, we got a Cox technician to come out and check the lines.  After some minor fixes to the filters and wiring for our house by the technician, the problem still continued.  I thought it might be that the modem was bad, so I switched to the Arris SB8200, which is our current modem.  The problem has continued with the new modem.  Any help would be appreciated to resolve this.

Event Log

The table below contains the log of events that the SB8200 has detected. This log can be important to the service provider to help diagnose and correct problems, if any should occur.

Time Priority Description
11-2-2018, 21:30:19 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
11-2-2018, 18:25:33 Warning(5) "Dynamic Range Window violation"
11-2-2018, 18:25:33 Warning(5) "RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
11-2-2018, 18:25:28 Notice(6) "DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 .;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
11-2-2018, 18:25:21 Notice(6) "TLV-11 - unrecognized OID;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:30 Warning(5) "DHCP WARNING - Non-critical field invalid in response ;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:28 Notice(6) "Honoring MDD; IP provisioning mode = IPv4"
1-1-1970, 0:0:18 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:27 Critical(3) "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:18 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
11-2-2018, 18:16:16 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:35 Critical(3) "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:18 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
10-31-2018, 15:27:46 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:18 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
10-30-2018, 17:51:44 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:18 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
10-23-2018, 14:6:8 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:2:4 Critical(3) "No Ranging Response received - T3 time-out;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=2c:31:24:60:43:22;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:2:1 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:1:53 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:28 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:56 Critical(3) "Telnet user logged in from IP address 192.168.100.101."
1-1-1970, 0:0:28 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=18:9c:27:f9:cf:39;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"

Connection

The status listed show the connection state of the cable modem. They are used by your service provider to evaluate the operation of the cable modem.

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 957000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
30 Locked QAM256 957000000 Hz 0.2 dBmV 34.7 dB 462 0
1 Locked QAM256 783000000 Hz 5.9 dBmV 38.3 dB 833 504
2 Locked QAM256 789000000 Hz 6.3 dBmV 38.6 dB 369 0
3 Locked QAM256 795000000 Hz 6.4 dBmV 38.6 dB 231 0
4 Locked QAM256 801000000 Hz 6.9 dBmV 39.0 dB 180 0
9 Locked QAM256 831000000 Hz 5.7 dBmV 38.1 dB 7303 4762
10 Locked QAM256 837000000 Hz 4.7 dBmV 37.8 dB 518 0
11 Locked QAM256 843000000 Hz 5.2 dBmV 37.8 dB 828 0
12 Locked QAM256 849000000 Hz 3.9 dBmV 37.2 dB 1195 0
17 Locked QAM256 879000000 Hz 4.6 dBmV 37.7 dB 758 0
18 Locked QAM256 885000000 Hz 3.5 dBmV 37.1 dB 902 0
19 Locked QAM256 891000000 Hz 3.9 dBmV 37.3 dB 928 0
20 Locked QAM256 897000000 Hz 3.0 dBmV 36.8 dB 977 0
21 Locked QAM256 903000000 Hz 3.0 dBmV 36.8 dB 873 0
22 Locked QAM256 909000000 Hz 1.9 dBmV 35.8 dB 1995 0
25 Locked QAM256 927000000 Hz 1.5 dBmV 35.6 dB 681 0
26 Locked QAM256 933000000 Hz 1.6 dBmV 35.7 dB 1045 0
27 Locked QAM256 939000000 Hz 0.3 dBmV 34.7 dB 930 0
28 Locked QAM256 945000000 Hz 1.1 dBmV 35.4 dB 660 0
29 Locked QAM256 951000000 Hz -0.3 dBmV 34.4 dB 652 0
33 Locked QAM256 357000000 Hz 8.8 dBmV 40.3 dB 0 0
34 Locked QAM256 363000000 Hz 9.0 dBmV 40.4 dB 0 0
35 Locked QAM256 369000000 Hz 9.5 dBmV 40.7 dB 0 0
36 Locked QAM256 375000000 Hz 9.6 dBmV 40.7 dB 0 0
37 Locked QAM256 381000000 Hz 9.9 dBmV 40.8 dB 0 0
38 Locked QAM256 387000000 Hz 10.2 dBmV 40.8 dB 0 0
41 Locked QAM256 405000000 Hz 10.5 dBmV 40.9 dB 0 0
42 Locked QAM256 411000000 Hz 10.8 dBmV 41.1 dB 0 0
43 Locked QAM256 417000000 Hz 10.6 dBmV 41.1 dB 0 0
44 Locked QAM256 423000000 Hz 10.8 dBmV 41.1 dB 0 0
45 Locked QAM256 429000000 Hz 10.5 dBmV 40.9 dB 0 0
46 Locked QAM256 435000000 Hz 11.0 dBmV 41.2 dB 0 0
159 Locked Other 300000000 Hz 12.4 dBmV 41.2 dB 23165813 0

Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 1 Locked SC-QAM 16900000 Hz 6400000 Hz 43.0 dBmV
2 2 Locked SC-QAM 23500000 Hz 6400000 Hz 43.0 dBmV
3 3 Locked SC-QAM 29900000 Hz 6400000 Hz 44.0 dBmV
4 4 Locked SC-QAM 36300000 Hz 6400000 Hz 44.0 dBmV

Current System Time: Sun Nov 4 08:40:20 2018

2 Replies

  • Hi CatsJam, if you bypass the router temporarily and connect a device directly to the modem with an ethernet cord, do the disconnects continue? Don't forget to reset the modem after changing the connections. -Becky, Cox Support Forums Moderator